Interpretive Summary: Soil aggregation is a complex process that includes the input of glues from microorganisms. Glues that stabilize aggregates were thought to be produced by bacteria growing on organic matter. Bacteria produce sticky polysaccharides as a protection against desiccation. We are beginning to understand the importance of the recent discover of a glue produced in large amounts by one group of soil fungi. The fungi are the arbuscular mycorrhizal fungi (AMF) and the glue was named glomalin after Glomales - the taxonomic order of this group of fungi. Glomalin concentrations in soil are related to aggregate stability and can be enhanced by cropping systems used for sustainable agriculture. Examples of this are give for three different geographic locations - North Carolina, Maryland, and North Dakota. Glomalin and aggregate stability were related to: (i) length of time soil was covered with growing plants in North Carolina and no-till management of corn in Maryland and North Dakota. The North Dakota study showed seasonal variation in aggregate stability and glomalin. These examples show that inputs of glomalin should be considered a part of sustainable agricultural management practices.

Technical Abstract:
Soil aggregation is a complex process that includes the input of glues from microorganisms. Glues that stabilize aggregates were thought to be produced by bacteria growing on organic matter. Bacteria produce sticky polysaccharides as a protection against desiccation. We are beginning to understand the importance of the recent discover of a glue produced in large amounts by one group of soil fungi. The fungi are the arbuscular mycorrhizal fungi (AMF) and the glue was named glomalin after Glomales - the taxonomic order of this group of fungi. Glomalin concentrations in soil are related to aggregate stability and can be enhanced by cropping systems used for sustainable agriculture. Examples of this are give for three different geographic locations - North Carolina, Maryland, and North Dakota. Glomalin and aggregate stability were related to: (i) length of time soil was covered with growing plants in North Carolina and no-till management of corn in Maryland and North Dakota. The North Dakota study showed seasonal variation in aggregate stability and glomalin. These examples show that inputs of glomalin should be considered a part of sustainable agricultural management practices.